I had the same problem with a Seagate DAT drive on the Adaptec 2940UW. 
 I just disabled the "Ultra Wide" option in my SCSI BIOS settings. 
 That seemed to do the trick.  Let me know if you find otherwise ...




/abp

--
Adam B. Plummer
Metamor Technologies, Ltd.
One North Franklin St. (Suite 1500)
Chicago, IL  60606
WWW:	http://www.metamor.com/
E-Mail:	adam.plummer@metamor.com
Phone:	(312) 251-2455
Fax:	(312) 251-2999
Pager:	(312) 910-0395 or adam.plummer@pager.metamor.com


-----Original Message-----
From:	tron@lyssa.owl.de [SMTP:tron@lyssa.owl.de]
Sent:	Wednesday, February 19, 1997 9:16 PM
To:	port-i386@NetBSD.ORG
Subject:	Adaptec 2940 UW vs. Sony SDT 2000

	Hi,

today I replaced my good old NCR 53c810 by an Adaptec 2940UW. After
adapting the mapping everything works fine except my Sony SDT 2000
DAT tape. If I try to write to it with "tar" I get error messages
like this:

st2(ahc0:4:0): timed out in dataout phase, SCSISIGI == 0x0
st2(ahc0:4:0): BUS DEVICE RESET message queued.
Bus Device Reset Message Sent
st2(ahc0:4:0): timed out in message out phase, SCSISIGI == 0xa4
ahc0: Issued Channel A Bus Reset #1. 1 SCBs aborted

Here's what the kernel says during system startup about the DAT:

ahc0:A:4: refuses WIDE negotiation.  Using 8bit transfers
ahc0: target 4 synchronous at 5.0MHz, offset = 0x7
st2 at scsibus1 targ 4 lun 0: <SONY, SDT-2000, 2.05> SCSI2 
1/sequential removable
st2: drive empty

A Tandberg TDC 3660 and an Exabyte 8200S both work with the Adaptec,
the Sony SDT 2000 works with the NCR.

I would like to know if anybody else uses such a tape drive under 
NetBSD
in conjuction with an 2940(UW) because I'm not sure if this a bug in
the driver or some kind of hardware problem.

--
Matthias Scheler 
                               http://home.pages.de/~tron/